<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <meta charset="utf-8">
    <title>Title</title>
</head>
<body>
<c:if test="${flag}" var="abc" scope="request">
    表达式结果为 true，显示当前内容:
</c:if>
${abc}
</body>
</html>
